Confused about upgrades

[Bullett00th]

When I unlock an aircraft in the tech tree, it unlocks the following progression options - usually a few upgrades leading to the next plane.

But I can't figure out where do these upgrades apply? Are they for the last unlocked aircraft in the tree? For a plane class? The whole branch of the tree?

[paomayo]

They're available for all the playable planes (some parts work better with what it was meant to be used for - i.e. bomb payload for a plane that has a bomb-type special weapon). The main thing to keep in mind is the amount of slots is available depending on the aircraft. Higher-lever parts eat up more slots,

I'll leave this Acepedia article for reference:

https://acecombat.fandom.com/wiki/Tuning?so=search#Console_games

[Bullett00th]

Thanks!

Apparently I've gone through like 16 missions without ever installing a single upgrade because I skipped the screen where you add them.

That said the only one I felt genuine use from is the extra secondary weapons.